1. Field of the Invention:
The present invention relates to a method of and an apparatus for controlling the camber of the rear wheels of a four-wheel-steerable vehicle (hereinafter referred to as a "4WS vehicle") with respect to ground.
2. Description of the Relevant Art:
Ordinary two-wheel-steerable vehicles (hereinafter referred to as a "2WS vehicle") have only front wheels steerable with rear wheels not steerable. It has been proposed in U.S. Pat. application No. 51,846, filed May 18, 1987, that the camber of the rear wheels of such a 2WS vehicle is controlled to tilt the rear wheels in the same direction as that in which the front wheels are steered, for thereby imposing a camber thrust on the rear wheels to improve the steering response and cornering capability of the vehicle when it changes its courses or lanes.
U.S. Pat. Nos. 4,313,514 and 4,412,594 disclose 4WS vehicles in which rear wheels as well as front wheels can be steered. The steering response and cornering capability of the 4WS vehicles are increased by steering the rear wheels in the same direction as or opposite direction to the front wheels dependent on the steering angle of the front wheels and the speed of travel of the vehicle.
In the 4WS vehicle, generally, the front and rear wheels are steered in opposite directions when the steering wheel is turned through a large angle in medium and low vehicle speed ranges, and are steered in the same direction when the steering wheel is turned through a small angle in a high vehicle speed range.